Northern line (Boston Underground)

Northern line
	Legend
	IntraRail to
	Zaquar North Station
	Zaquar-Fort Yaxier
	Corridor
	Zaquar
	Boston

Northern line
Northern line
	A Northern line train at Border's Alley
Stations	6
Color on Tube map	Black
Service
Type	Rapid transit
System	Boston Underground
Depot(s)	Waterloo, Downtown Crossing
Rolling stock	1995 Stock (5 cars per trainset)
Technical
Character	Deep-tube
Transport for Boston rail lines
Boston Underground
	Bakerloo
	style="border: 8px solid #E32017 border-width 0 1em; text-align: center;" \| Central
	style="border: 8px solid #FFD300 border-width 0 1em; text-align: center;" \| Circle
	style="border: 8px solid #00782A border-width 0 1em; text-align: center;" \| District
	style="border: 8px solid #F3A9BB border-width 0 1em; text-align: center;" \| Hammersmith & City
	style="border: 8px solid #A0A5A9 border-width 0 1em; text-align: center;" \| Jubilee
	style="border: 8px solid #9B0056 border-width 0 1em; text-align: center;" \| Metropolitan
	style="border: 8px solid #000000 border-width 0 1em; text-align: center;" \| Northern
	style="border: 8px solid #003688 border-width 0 1em; text-align: center;" \| Piccadilly
	style="border: 8px solid #0098D4 border-width 0 1em; text-align: center;" \| Victoria
	style="border: 8px solid #95CDBA border-width 0 1em; text-align: center;" \| Waterloo & City
MBTA
	style="border: 8px solid #da291c border-width 0 1em; text-align: center;" \| Red
	style="border: 8px solid #ed8b00 border-width 0 1em; text-align: center;" \| Orange
	style="border: 8px solid #00843d border-width 0 1em; text-align: center;" \| Green
	style="border: 8px solid #003da5 border-width 0 1em; text-align: center;" \| Blue
	style="border: 8px solid #7c878e border-width 0 1em; text-align: center;" \| Silver
Other lines
	style="border: 8px solid #00A4A7 border-width 0 1em; text-align: center;" \| Docklands Light Railway
	style="border: 8px solid #EE7C0E border-width 0 1em; text-align: center;" \| Overground
	style="border: 8px solid #7156A5 border-width 0 1em; text-align: center;" \| Crossrail
	style="border: 8px solid #80276c border-width 0 1em; text-align: center;" \| MBTA Commuter Rail

The Northern line is a Boston Underground line that runs north-south through Boston paralleling the MRT Zephyr Line. For all of its length, the line runs underground in deep-level tube tunnels.